Gets entire view hierarchy with precise frame coordinates (x, y, width, height) for all visible elements. Use this before UI interactions or after layout changes - do NOT guess coordinates from screenshots. Returns JSON tree with frame data for accurate automation.
AI agents call describe_ui to retrieve information from Sl Test without modifying anything — typically the context-gathering step in research, monitoring, and reporting workflows, before the agent takes action elsewhere.
This tool queries and retrieves UI structure data without modifying, executing, or deleting anything. It is a read-only operation providing layout information for downstream automation tasks, similar to inspecting DOM or accessibility trees. The low severity reflects that misuse (e.g., exfiltrating layout data) poses minimal risk compared to other tool categories.
From the tool's definition Tool 'describe_ui' retrieves view hierarchy and frame coordinates; the description explicitly states it 'Gets entire view hierarchy' and 'Returns JSON tree' - purely informational operations with no side effects or modifications.
Risk signalsBulk/mass operation — affects multiple targets
Attacks that exploit this kind of access
Gets entire view hierarchy with precise frame coordinates (x, y, width, height) for all visible elements. Use this before UI interactions or after layout changes - do NOT guess coordinates from screenshots. Returns JSON tree with frame data for accurate automation. It is categorised as a Read tool in the Sl Test MCP Server, which means it retrieves data without modifying state.
Register the Sl Test MCP server in PolicyLayer and add a rule for describe_ui: allow, deny, rate-limit, or require approval. Point your MCP client at the PolicyLayer proxy URL and the rule is enforced on every call, before it reaches Sl Test. Nothing to install.
describe_ui is a Read tool with low risk. Read-only tools are generally safe to allow by default.
Yes. Add a rate_limit block to the describe_ui rule in your PolicyLayer policy. For example, setting max: 10 and window: 60 limits the tool to 10 calls per minute. Rate limits are tracked per agent session and reset automatically.
Set action: deny in the PolicyLayer policy for describe_ui. The AI agent will receive a policy violation error and cannot call the tool. You can also include a reason field to explain why the tool is blocked.
describe_ui is provided by the Sl Test MCP server (sampsonky/xcodebuildmcp). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.
Every MCP server has a record like this.
Type a name, get the same breakdown: verified identity, auth posture, risk grade, capabilities, recommended policy.
Teams ship this data inside their own products. See what a licence covers →